为解决汽车轮胎压力无线监测系统(TPMS)电能自给问题,应用压电换能原理,提出将PZT5压电振子复合在轮胎内底面,把运行中的机械能转换为电能为无线发射模块供电的思想,设计了一种压电陶瓷轮胎发电机。建立了双层膜压电振子的有限元(FEA)模型,运用ANSYS 11.0对不同尺寸的振子进行静力和瞬态分析,得出设计振子尺寸的依据。针对单个振子发电量低的状况,提出采用阵列方式增大发电量的方案,设计了一种多振子电量耦合输出调节控制电路。选择振子尺寸为40mm×15mm,实验得到单片压电振子在15 Hz固定形变的激励下,有效输出电流为5μA,峰值电压为5 V以上。当振子数量为40个以上时,轮胎发电输出的功率能满足TPMS休眠模式耗电30μW,发射耗电35mW,间歇时间30 s的需要。实验表明,压电阵列式轮胎发电机平均输出功率为150～350μW,瞬时输出功率可达到50mW。

A novel power generator in the tire which is applied in a wireless Tire Pressure Monitor System(TPMS) was designed. The piezoelectric convertor constructed by bender arrays was merged to the inner surface of a tire to transform the mechanical deformation into the electric power and supply to the sensors of TPMS. A Finite Element Model(FEM) for the convertor was established based on the second piezoelectric function and the piezoelectric convertor with different sizes was analyzed by ANSYS 11.0 in a transient method. Then,a target of 6 cm² was selected to observe its characteristics,and the effective current is 5 μA. As the wireless sending component needs 10 mA every 30 s,an array with 40 piezoelectric convertors was used in the generator and a power conditioning circuit with a multiple path charge coupling module was also designed. Experiments show that when the frequency of tire rotation is 15 Hz,the average power through the conditioning circuit is 150－350 μW and the instantaneous power can reach 50 mW,which proves that the power generator can work efficiently.